We study the transcription of the E. coli galactose operon as a model system for gene regulation. This operon is subject to both negative regulation by a specific repressor protein and to positive control by cyclic AMP and the cyclic AMP receptor protein (CRP). We attempt to define the precise protein-DNA interactions which control the regulation of this operon. The nucleotide sequence of the regulatory region of the galactose operon has been determined. There are two closely spaced startpoints for transcription in the galactose operon and presumably two promoters; one controlled by CRP and cyclic AMP, the other independent of those factors. We are presently defining which nucleotides in the sequence we have determined interact respectively with the gal repressor, RNA polymerase and CRP.